ISIS Segment Routing IPv6 (SRv6) with FRR (FRRouting) and Ubuntu (WSL)


This post describes the ISIS Segment Routing IPv6 (SRv6) with FRR (FRRouting) and Ubuntu (WSL).

Code repositories

Credits:
Code authours: Carmine Scarpitta and Dmytro Shytyi.
[PART1] SRv6 multiple segs SIDs series of patches
[PART2] ISIS SRv6 series of patches

I would like to thank for a review: @cscarpitta @pushpasis @donaldsharp @routingrocks and @riw777.

Linux support

Ubuntu 22.04 within WSL was used for the testbed with kernel that has activated LW_TUNNELs (CONFIG_IPV6_SEG6_LWTUNNEL)

Consider to activate Sysfs variable such as “Seg6 seg6_enabled” and/or “sysctl -w net.ipv6.conf.all.forwarding=1”.

FRR configuration

r1:

r2:

r7:

Display SRv6 route on r1

FRR:

iproute2:

Display ISIS SRv6 seg6local behavior on R2

The same seg6local behavior is bootstrapped on r3, r4, r5, r6, r7 nodes.

r2 router:

r5 router:

Testbed consoles presented with routers indexes

This figure (if font is too small, please open figure in new separate window) is related to the network topology presented in the top of article. This figure describes router placement that doesn’t change in future figures.
Also you may find parts of configuration presented in rectangles.

Testbed – echo request/reply based on ISIS SPF (RED Line in the first figure)

This figure (if font is too small, please open figure in new separate window) is related to the network topology presented in the top of article. This figure describes the echo “request”/”reply” process in regular setup. Echo request is sent via SPF (r1-r2-r3-r7) – red line in the fist figure. Echo reply is returned in vise-versa manner.

Testbed – echo request/reply based with SRv6 features (Blue SRv6 Low-Latency tunnel)

This figure (if font is too small, please open figure in new separate window) is related to the network topology presented in the top of article. This figure describes the echo “request”/”reply” process witch SRv6 features.
Echo request is sent via the low-latency path (r1-r4-r5-r6-r7) using the SRv6 route and returned by regular path (r7-r3-r2-r1).

Publication date: 07/28/2023 3:57AM